.\"
.\" Copyright (c) 2018 Netflix, Inc.
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions, and the following disclaimer,
.\"    without modification, immediately at the beginning of the file.
.\" 2. The name of the author may not be used to endorse or promote products
.\"    derived from this software without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
.\" ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.Dd July 8, 2018
.Dt Q_QADDI 3
.Os
.Sh NAME
.Nm Q_QADDI ,
.Nm Q_QDIVI ,
.Nm Q_QMULI ,
.Nm Q_QSUBI ,
.Nm Q_QFRACI ,
.Nm Q_QCPYVALI
.Nd fixed-point math functions which apply integers to a Q number
.Sh SYNOPSIS
.In sys/qmath.h
.Ft int
.Fn Q_QADDI "QTYPE *a" "ITYPE b"
.Ft int
.Fn Q_QDIVI "QTYPE *a" "ITYPE b"
.Ft int
.Fn Q_QMULI "QTYPE *a" "ITYPE b"
.Ft int
.Fn Q_QSUBI "QTYPE *a" "ITYPE b"
.Ft int
.Fn Q_QFRACI "QTYPE *q" "ITYPE n" "ITYPE d"
.Ft int
.Fn Q_QCPYVALI "QTYPE *q" "ITYPE i"
.Sh DESCRIPTION
The
.Fn Q_QADDI ,
.Fn Q_QDIVI ,
.Fn Q_QMULI
and
.Fn Q_QSUBI
functions add, divide, multiply or subtract
.Fa b
to/by/from
.Fa a
respectively, storing the result in
.Fa a .
.Pp
The
.Fn Q_QFRACI
function computes the fraction
.Fa n
divided by
.Fa d
and stores the fixed-point result in
.Fa q .
.Pp
The
.Fn Q_QCPYVALI
function overwrites
.Fa q Ap s
integer and fractional bits with the Q representation of integer value
.Fa i .
.Pp
All of those functions operate on
the following data types:
.Vt s8q_t ,
.Vt u8q_t ,
.Vt s16q_t ,
.Vt u16q_t ,
.Vt s32q_t ,
.Vt u32q_t ,
.Vt s64q_t ,
and
.Vt u64q_t ,
which are referred to generically as
.Fa QTYPE .
The
.Fa ITYPE
refers to the
.Xr stdint 7
integer types.
.Pp
For more details, see
.Xr qmath 3 .
.Sh RETURN VALUES
.Fn Q_QADDI ,
.Fn Q_QDIVI ,
.Fn Q_QMULI ,
.Fn Q_QSUBI ,
.Fn Q_QFRACI
and
.Fn Q_QCPYVALI
functions return 0 on success, or an errno on failure.
.Er EINVAL
is returned for divide-by-zero.
.Er EOVERFLOW
and
.Er ERANGE
are returned for overflow and underflow respectively.
.Sh SEE ALSO
.Xr errno 2 ,
.Xr qmath 3 ,
.Xr stdint 7
.Sh HISTORY
The
.Xr qmath 3
functions first appeared in
.Fx 13.0 .
.Sh AUTHORS
.An -nosplit
The
.Xr qmath 3
functions and this manual page were written by
.An Lawrence Stewart Aq Mt lstewart@FreeBSD.org
and sponsored by Netflix, Inc.
